President Joe Biden has signed a bill into law that requires ByteDance, the China-based parent company of TikTok, to divest the app within a year to avoid an effective ban in the US. The bill was passed as part of a foreign aid package and gives ByteDance an initial nine months to sort out a deal, with the possibility of a three-month extension. TikTok plans to challenge the law in court, which could delay enforcement. The company's algorithm and user data are key concerns in the potential sale.